Vec2::Vec2(double u,double v){
    this->u = u;
    this->v = v;
}
Vec2 Vec2::operator+(const Vec2&b){
    Vec2 temp(u + b.u,v + b.v);
    return temp;
}
bool operator!=(const Vec2&a,const Vec2&b)
{
    return (a.u!= b.u|| a.v != b.v);
}

ostream&operator<<(ostream&os,const Vec2&c){
   os<<"u="<<c.u<<",v="<<c.v;
    return os;
}
istream&operator>>(istream&is,Vec2&c){
   
   is>>c.u>>c.v;
   return is;
}